I want to build up a 89-91 13b for my first gen but I am worried about porting with the diffuser in the exhaust port. Is this hard to grind or torch out? Anyone done this?

 

Just use TII housings, they don't have diffusers.

read this page........

http://www.mazdatrix.com/faq/6pexh.htm

 

THats wher I learned of the problem. is that the common consensus on fixing it. I just dont want to spend the money on new rotor housings. If i can grind it out I will

 

Yeah you can grind it out, but it will take forever and you'll go through a lot of bits. That thing is extremely hard steel.

 

what does the diffuser do exactly?

 

You can try drilling out the side dowell pins that hold the diffuser in, use the search, I had my own personal battle with this and posted a lot of into on it.

 

I believe they serve two purposes. One Is to seperate, somewhat, the exhaust pulses of the outcoming exhaust, therefore muffling out the noise. Also, with the seperation In effect, It cools the exhaust stream that comes out by making It less concentrated by seperating It.

 

is that why 2nd gens sound really deep insted of really chainsawish?

 

Their main purpose is to help quiet the exhaust. That is also the reason for the shoebox of an exhaust manifold the n/a's have. The turbos didn't need them since the turbo itself helps muffle the engine somewhat. They also wanted the full exhaust energy to spin the turbo. 2nd gens can sound like a chainsaw or superbike. That is just the factory exhaust.

You can grind out those diffusers if you want to. They are made from unobtainium, a rather unknown supercompound from planet Krypton! Damn hard steel. Use a die grinder with a carbide bit (or several) not a dremel. Plan on a lot of time. It would be beneficial though since you can now enlarge the exhaust port. Good luck.

Fred

 

I think I will try and port it and save money but if need be I think ill get the Turbo housings.